Cutting members may be divided into a reciprocating type, a rotating type and a swinging type depending on the operation mode. The different types of cutting members and operation modes generally require different types of clamping devices. In a conventional electric circular saw, the saw blade is mounted by screwing a flange to the threaded portion of a shaft with a spanner to clamp the cutting member between the shaft shoulder and the flange and then compressing it with friction force. When it needs to be replaced, the flange may be released by the spinner or pre-released by a screw driver and a hammer and then screwed off by the spinner. In the conventional electric circular saw, the saw blade needs to be mounted with a special tool, and the process for mounting and clamping the saw blade is laborious, unsafe and not easily operated, while the device for clamping the saw blade is also relatively larger in size.